Enhancement of entanglement in one-dimensional disordered systems

TL;DR

This paper investigates how different types of disorder affect quantum entanglement in one-dimensional electronic systems, revealing that off-diagonal disorder can significantly enhance entanglement near half filling.

Contribution

It demonstrates that off-diagonal disorder can unexpectedly increase entanglement, contrasting with the entanglement decrease caused by diagonal disorder in disordered 1D systems.

Findings

Off-diagonal disorder enhances entanglement near half filling.

Diagonal disorder decreases entanglement compared to ordered systems.

Entanglement can be up to 15% larger with off-diagonal disorder.

Abstract

The pairwise quantum entanglement of sites in disordered electronic one-dimensional systems (rings) is studied. We focus on the effect of diagonal and off diagonal disorder on the concurrence $C_{ij}$ between electrons on neighbor and non neighbor sites $i,j$ as a function of band filling. In the case of diagonal disorder, increasing the degree of disorder leads to a decrease of the concurrence with respect to the ordered case. However, off-diagonal disorder produces a surprisingly strong enhancement of entanglement. This remarkable effect occurs near half filling, where the concurrence becomes up to 15% larger than in the ordered system.